Image reproduction machines such as electrophotographic printers and copiers are required to print on media, e.g. paper, of various sizes, e.g. letter and A4. Photographic printers such as those used in minilabs are required to print on a wide range of sizes, including 8″×10″, 4″×8″, and 3.5″×5″. Such machines typically include a paper-feed tray for feeding cut sheets of paper of various sizes sequentially into the printer. However, such trays typically have a minimum media size, and specifically a minimum media width. In order to use media with a width smaller than the minimum with such a printer, a different tray or a specialized adapter is required. Furthermore, it is desirable to make an adapter which requires no changes to the printer. Additionally, it is important that media be fed with reduced skew, i.e. angular deviation from sheet to sheet.
U.S. Pat. No. 5,085,419 to Bell describes a feeder insert tray for feeding smaller media. The insert tray is placed on top of larger media already in a media tray in the printer. This permits feeding smaller media from the insert tray without having to remove the larger media from the media tray. However, this scheme requires the media tray to contain some larger-size media. Moreover, the insert tray can fail to provide consistent performance over long print runs, and is subject to operator error during insertion and removal. Moreover, this scheme does not permit the use of a spring plate for lifting the media, as is common on the residential and business printers.
U.S. Patent Publication No. 2004/0253032 to Kojima describes an auxiliary tray frame attached to a tray unit for holding small-size media. However, the auxiliary tray frame extends laterally beyond the footprint of the tray unit, and therefore requires a tray unit and printer designed to accept the auxiliary frame. This makes retrofitting a printer to print on smaller-sized media very difficult with this scheme. Furthermore, this scheme uses a bias spring to hold media laterally, and so does not provide a smooth, low-skew path for the media to be extracted from the tray.
U.S. Pat. No. 7,376,381 to Black describes a paper guide mechanism installed in a printer tray to guide paper having a reduced width compared to a particular allowed paper size. However, this scheme can require fastening the paper guide mechanism to the printer tray, increasing the time and cost of media-size changes. Moreover, this scheme does not provide improved skew performance over the original tray.
There is a continuing need, therefore, for an improved media-feed mechanism which permits using media that is narrower than the minimum width of a particular media tray.